1. Field of the Invention
The present invention reltes to a method for patterning data storage media with optical or capacitive servo control patterns on the surface of said storage media.
2. Description of Related Art
Servo control systems for magnetic recording drives require control patterns on the disks or tape units for dynamically positioning the read/write head. The control patterns must be built into the units in such a way that they are compatible with the magnetic recording medium employed and re easily sensed by the read/write head. Ideally, the control pattern does not interact with readout of the magnetically recorded signal.
One technique, which has been used by those working in this field, has been to directly incorporate with the data stored, the positioning information for the servo system. However, this system has been less than desirable, as the servo positioning information takes up valuable data storage space, and interferes with readout of the recorded data.
In response to this demand for a more data efficient method of incorporating servo control patterns with the data to be recorded, several alternative techniques have been developed.
For example, in IBM Technical Disclosure Bulletin, Volume 21, No. 1, pp. 4259-4260, (March 1979), Acosta et al teach embossing servo control tracks on a magnetic recording disk. The magnetic recording medium is taught as being made in the usual manner, followed by the stamping or embossing of said medium with a master die. In another attempt at incorporating servo control patterns on the recording media Kojima et al in U.S. Pat. No. 4,150,398, describe the optical formation of a disk recording by exposing a film of photoresist with a laser to produce grooves with irregularities at the bottom of the grooves, However, both of these systems have failed to yield a sufficiently accurate and sensitive mechanism by which the data file on the magnetic disk can be managed.
In a copending U.S. patent application Ser. No. 613,943 filed May 24, 1984 of Best et al, the formation of a data recording medium is described for carrying a data recording layer (e.g., magnetic or optical) with a thin metal servo control track layer located either above or below said recording layer. The thickness of the metal layer can be varied to provide a variable electromagnetic property, such as variable capacitance, to indicate position. While the application teaches how to embody the thin metal layer with a recording media, the application does not disclose a method of continuous format patterning the servo control layer on a recording medium.
It is therefore, an object of the present invention to develop a simple and efficient method for patterning thin metal servo control film patterns on magnetic recording media in a continuous manner.
It is another object of this invention to provide servo control patterns that do not interact or interfere with readout of the magnetically recorded information.